1. Field of the Invention
This invention generally relates to a bicycle wheel having a hub axle adapted to be mounted to a bicycle frame, a hub body rotatably supported on the hub shaft, an annular rim and a plurality of spokes extending inwardly from the rim to the hub body. More specifically, the present invention relates to the hub of the bicycle wheel with a freewheel being provided axially on one side of the hub body.
2. Background Information
Bicycling is becoming an increasingly more popular form of recreation as well as a means of transportation. Moreover, bicycling has also become a very popular competitive sport for both amateurs and professionals. Whether the bicycle is used for recreation, transportation or competition, the bicycle industry is constantly improving the various components of the bicycle. One particular component of the bicycle that has been extensively redesigned over the past years is the rear bicycle hubs. Rear bicycle hubs are constantly being redesigned to be lightweight yet more durable and stronger. Moreover, rear bicycle hubs have been redesigned over the years to have more sprockets or gears. In particular, most of today""s bicycles have at least seven sprockets. Moreover, some bicycles even have nine sprockets. There are demands for a simplified mounting structure and easy mounting method.
One popular form of drive train for a bicycle includes utilizing a plurality of sprockets that are mounted on the hub of the rear bicycle wheel. During pedaling, the bicycle chain engages one of the rear sprockets to rotate the rear wheel. When bicycle rider stops pedaling, the rear wheel should be able to continue to rotate while the sprockets remain stationary. Accordingly, the rear hub is provided with a freewheel that has a one-way clutch.
Freewheels are usually mounted on the rear hub of a bicycle for transmitting a driving force to the rear bicycle wheel in one rotation direction only. Freewheels are used so that the bicycle can advance freely without any rotation of the pedals. Freewheels include boss type freewheels which are mounted on the boss of the rear hub by being screwed onto the rear hub, and freehub type freewheels which are fastened to the rear hub as integral parts of the rear hub. Both types of freewheels are equipped with an outer tubular part, an inner tubular part which is installed radially inwardly of the outer tubular part so that the inner tubular part is free to rotate relative to the outer cylinder part, and a one-way clutch which is installed between the outer tubular part and inner tubular part for transmitting the driving force from the outer tubular part to the inner tubular part in one rotational direction only. The outer tubular part has a plurality of gears mounted thereon, while the inner tubular part is usually mounted on the rear hub of the bicycle.
Splines are formed between the sprockets and boss to prohibit relative rotation therebetween positively. Since this unit is used for the rear wheel of a bicycle, drive must be transmitted between the rear wheel axle and boss through a one-way mechanism. For this purpose, the boss is formed as an outer race of a one-way clutch, and the one-way clutch and inner race are disposed on an inner periphery of the boss.
As the number of rear gears or sprockets have increased over the years, the freewheel has become larger and heavier. Moreover, with the increased number of gears or sprockets, a wider range of torque is being applied from the sprockets to the freewheel. In addition, the spoke mounting portions of the rear hub have gotten closer together as the number of rear gears or sprockets have increased over the years. This results in a less stable and a less rigid wheel.
In view of the above, there exists a need for an improved rear hub assembly for a bicycle wheel which overcomes the above mentioned problems in the prior art. This invention addresses this need in the prior art as well as other needs, which will become apparent to those skilled in the art from this disclosure.
One object of the present invention is to provide a rear hub assembly for a bicycle wheel that is more stable and more rigid relative to conventional rear hub assemblies with an equal number of gears or sprockets.
Another object of the present invention is to provide a rear hub assembly for a bicycle wheel that has better performance in terms of strength and durability relative to conventional rear hub assemblies.
Still another object of the present invention is to provide a rear hub assembly with a freewheel that can support several sprockets in a compact manner.
Yet another object of the present invention is to provide a freewheel that is relatively easy to assemble and relatively inexpensive to manufacture.
The foregoing objects can be attained by providing a bicycle wheel basically has a central hub assembly, a plurality of spokes extending outwardly from the central hub assembly and an annular rim coupled to the outer ends of the spokes for supporting a tire. The central hub assembly has a hub axle, a hub unit, a freewheel and a plurality of sprockets. The hub axle has a center axis extending between a first frame mounting end and a second frame mounting end. The hub unit has a hub body, a first spoke mounting portion, a second spoke mounting portion and an interior passageway. The first spoke mounting portion is located adjacent a first end of the hub body. The second spoke mounting portion is located adjacent a second end of the hub body. The interior passageway extends through the hub body with the hub axle being rotatably supported therein. The freewheel is operatively coupled between the first end of the hub axle and the first end of the hub body. The sprockets are coupled to the freewheel and axially spaced apart along the freewheel. The sprocket assembly has an inner portion recessed within a recess of the first spoke mounting portion.
These and other objects, features, aspects and advantages of the present invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses preferred embodiment of the present invention.